Researchers conducting web-based research have trouble controlling who actually answers their on-line questionnaires, which places limits on their research due to the possibility of a. biased samples. b. the barnum effect. c. researcher bias. d. research participant bias.

Researchers conducting "'web-based research" have trouble controlling who actually answers their "on-line questionnaires", which places limits on their research due to the possibility of research participant bias.

Explanation:

true. earthquakes are felt whenever there is a slip around a fault in the rocks below the earth. this reorientation of faults create sesmic waves and is known as earthquake, the severity of which is measured in richter scale. these are more prominent in hilly regions as the rocks usually form faults to balance the pressures on it.